These studies attempt to elucidate the structure function relations of interferons in terms of the activities induced by physically diverse interferons forms. The interferons are studied for biological and physical differences when translated in different cellular and cell-free systems from interferon messenger RNAs extracted from various types of induced cells. Such studies indicate that distinct interferons from a given species can derive from different messenger RNAs as well as from post-translational modifications of the products of a single gene. Studies will be undertaken to isolate small active cores from interferons which will be characterized for each of the antiviral and non-antiviral activities and for in vivo efficacy compared to native interferon forms.